This invention relates to a novel process for processing and treating raw materials of marine products, and, more particularly, to a process for producing new food products having different quality and mouthfeel by treating raw materials of marine products such as fishes and shellfishes and seaweeds by means of a twin-screw extruder to texturize the same.
Fishes and shellfishes and seaweeds have been long eaten widely in Japan, and have been valuable sources of nutrition. However, in recent years, life style in Japan has become westernized and varied. The odor of fishes and shellfishes per se, the presence of bones and the troublesome removal of them while eating are disliked. Particularly, the younger generation eats less fishes and shellfishes. At the same time, the younger generation eats less seaweeds. In contrast, the consumption of meat has been increasing. On the other hand, fishes and shellfishes have not been so much consumed in Europe and America. However in recent years, they have been revaluated as low-calorie and high-protein food products, and are being eaten in gradually increasing amounts. If the products can be rendered into a more readily eatable form, it will be possible to make them more attractive to many people.
In order to prevent the trend toward fish-avoidance or to encourage more people to eat marine products, attempts have been made to render the fishes and shellfishes and seaweeds to a more readily eatable condition. For example, there have been developed a method for producing a food product having a meat-like fibrous texture by slowly freezing the fine flesh of fishes and shellfishes; and a process for producing a crab meat-like fibrous food product by molding and heating surimi paste in the noodlelike form from a nozzle or slit, or by extruding it in a coagulating solution to chemically modify the same. "Surimi" herein is a Japan term for mechanically deboned fish meat that has been washed with water and mixed with cryoprotectants for a good frozen shelflife. Thus, there have been provided a variety of food products which make possible enjoyable ingesting of fish meat protein differing in taste, flavor and mouthfeel from those of fish meat protein. Particularly, recently, crab meat-like food products are widely and favorably used.
While there have been provided meat-like or crab meat-like food products having different quality and mouthfeel from those of the fish and shellfish meat, the quality and mouthfeel in meat-like food products are not always satisfactory. Moreover, when surimi is used as a raw material, a water-soluble protein cannot be utilized because surimi is mechanically deboned fish meat that has been washed with water. Further, in producing such food products, apparatuses having respective functions are necessary in kneading, molding, heating and other steps, and therefore high cost and labor are necessary in the purchase, operation, and maintenance of such apparatuses. Furthermore, the development of food products capable of making the ingesting of seaweeds placement has not yet been sufficient.
Various studies have been carried out in order to provide a process for producing a new food product wherein raw materials for marine products such as fishes, shellfishes and seaweeds are treated by a simplified apparatus or process to provide food products which have different quality and mouthfeel from those of these materials, which retain water-soluble proteins and salt-soluble proteins, and which can be enjoyably eaten. We have now found that, when the raw materials of marine products such as surimi and chopped fish flesh which is mechanically separated with a deboner are treated by means of a twin-screw extruder, they can be easily textured by one apparatus and a delicious food product having new flavor and mouthfeel characteristics can be produced.